Field of the Invention
The present invention relates to a technique of improving a vehicle side impact sensing assembly in which a side impact sensor is installed on a center tunnel.
Description of the Related Art
A center tunnel is positioned in the center of the vehicle body in the vehicle width direction, and extends in the back-and-fourth direction of the vehicle body. A side impact sensor installed on this center tunnel senses an impact load which acts sideways on the vehicle body, that is, a so-called side impact load, and outputs an expansion signal to an airbag. A vehicle side impact sensing assembly having an arrangement like this is known from, for example, Japanese Patent Laid-Open No. 10-114256.
In this vehicle side impact sensing assembly known by Japanese Patent Laid-Open No. 10-114256, a horizontal-plate-like bracket (reinforcement) is formed on the upper surface of the center tunnel. This bracket is overlaid on the upper surface of the center tunnel, and mounting flanges projecting downward are formed on the two sides in the vehicle width direction. The left and right mounting flanges are attached to the left and right side surfaces of the center tunnel. A boss portion projecting upward is formed on the upper surface of the bracket. A side impact sensor is screwed to the upper surface of this boss portion.
It is necessary to firmly fix the bracket to the center tunnel in order to sufficiently and rapidly transmit a side impact load from the center tunnel to the side impact sensor while minimizing damping.
Generally, the height of the center tunnel is determined by taking account of various requirements demanded for each vehicle type, for example, the rigidity and strength of the whole vehicle body, the layout relationship between various members (for example, a shift lever and parking brake) positioned near the center tunnel, and the comfortableness of the interior. On the other hand, to increase the degree of freedom of design, it is preferable to be able to uniquely set the height of the side impact sensor independently of the height of the center tunnel.
In Japanese Patent Laid-Open No. 10-114256, it is possible to appropriately set the height of the upper surface of the bracket with respect to the center tunnel. To this end, the length of the left and right mounting flanges in the vertical direction need only be increased in accordance with the increase in height of the upper surface of the bracket with respect to the center tunnel. However, the lower surface of the horizontal-plate-like bracket is spaced apart upward from the upper surface of the center tunnel. This makes it impossible to unlimitedly firmly fix the bracket to the center tunnel. Also, when the bracket has the arrangement like this, the rigidity of the bracket itself cannot unlimitedly be increased. Accordingly, some improvement is necessary to sufficiently and rapidly transmit a side impact load from the center tunnel to the side impact sensor while minimizing damping. However, if the arrangement of the bracket is complicated, the manufacturing cost of the bracket increases.